surface within the gates had again become 1.50 m. higher. The whole ground within the fortification-walls was covered with the houses of the fourth city, their ground-plans having no regular form, but consisting, like the houses of the third settlement, of small chambers irregularly grouped together. The house-walls were built of a masonry of small quarry-stones joined with clay; but their dimensions were in general still smaller than those of the house-walls of the third city; we even see some house-walls only 0.30 m. thick. Besides, some of the house-walls were built of bricks, partly baked, partly unbaked. I call the attention of visitors to a wall of unbaked bricks, which may still be seen in the great block of débris, marked G on Plan VII., which has remained standing to the south of the temple A. The bricks are made of clay mixed with straw, and are 0.45 m. square and 0.07 m. high; they are joined with a cement of a whitish clay. The thickness of the walls, only one brick in breadth, measures, inclusive of the coating on both sides, 0.47 m. Considering the thinness of most of the house-walls of this fourth settlement, it is not probable that there could have been an upper story above the ground floors, which are still partially preserved: in fact, as in the third settlement so also in the fourth, most houses appear to have had only a ground floor. Both these settlements, as brought to light by the excavations, certainly give the impression of mere villages. No tiles were found in the fourth settlement, for, as in the preceding cities, all the houses were roofed with horizontal terraces, which, as we still see in the villages of the Troad, were made of wooden beams, reeds, and a layer of clay about 0.25 m. thick. It is especially the existence of these horizontal terraces, the clay of which is constantly being washed away by the rain and must always be renewed, that explains that rapid accumulation of the ground, which we find in the prehistoric settlements on the hill of Hissarlik, and which has never yet been observed elsewhere in anything like such
